Stacked cooler

ABSTRACT

A stacked cooler includes flow pipes that are stacked, each of the flow pipes having a flat shape and including a medium passage in which a heat medium flows, a heat exchange object that is disposed between each adjacent two of the flow pipes and is clamped between their flat planes, a protruding pipe part that is connected to at least one of the flow pipes and protrudes in a stacking direction of the flow pipes, and a load restraining part that restrains a load applied to a connection portion of the at least one of the flow pipes to the protruding pipe part as compared with a load applied to the other portion of the at least one of the flow pipes.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is based on Japanese Patent Application No. 2013-178800filed on Aug. 30, 2013, and Japanese Patent Application No. 2013-244981filed on Nov. 27, 2013, the disclosures of which are incorporated hereinby reference.

TECHNICAL FIELD

The present disclosure relates to a stacked cooler in which flow pipesand heat exchange objects are alternately stacked, the flow pipes havinga heat medium circulated therein.

BACKGROUND ART

A power converter such as a DC-DC converter is used for hybrid cars andelectric vehicles. The power converter is provided with a coolerincluding a semiconductor module in which a semiconductor element suchas a switching element is built and a heat exchange part to cool thesemiconductor module. As the cooler used for the power converter, forexample, a cooler shown in a patent document 1 can be given.

In the patent document 1 a power converter is disclosed which isprovided with a cooler having a heat exchange part constituted of aplurality of cooling pipes. In the heat exchange part, a plurality ofsemiconductor modules and a plurality of cooling pipes are alternatelystacked, so the heat exchange part is constituted in such a way that thesemiconductor modules can exchange heat with a refrigerant flowing inrefrigerant passages formed in the cooling pipes and hence can be cooledby the refrigerant.

PRIOR ART DOCUMENT Patent Document Patent Document 1: JP 2011-228580A

However, the cooler disclosed in the patent document 1 has the followingproblem. The power converter is requested to reduce its size and isrequested to reduce the size of the heat exchange part that occupiesmost part of a volume also in the cooler. In order to reduce the size ofthe heat exchange part, a connection part of a front end cooling pipe,which is arranged at one end in a stacking direction in the heatexchange part, and a refrigerant introduction pipe and a refrigerantdischarge pipe, which are connected to the front end cooling pipe andcirculate the refrigerant in the refrigerant passage, needs to bereduced in size. In this case, when an external force is applied to therefrigerant introduction pipe and the refrigerant discharge pipe, astress is easily concentrated at the connection part. For this reason,the stress in the front end cooling pipe is apt to be increased andhence to be easily deformed.

There has been known a stacked cooler in which flow pipes, each of whichhas a heat transfer medium circulated therein, and electronic parts,each of which constitutes a heat exchange object, are alternatelystacked and which makes the heat transfer medium exchange heat with theelectronic parts to thereby cool the electronic parts (for example, seepatent document 1). In this regard, each of the adjacent flow pipes isprovided with a protruding pipe part to protrude in the stackingdirection and the protruding pipe parts of the respective flow pipes arejoined to each other, whereby the respective flow pipes communicate witheach other.

The patent document 1 proposes a technique for restraining the inner finfrom being shifted in position in the flow pipe in the stacked coolerhaving an inner fin (wavy fin) provided in the flow pipe so as toaccelerate a heat exchange between the heat transfer medium and theelectronic part.

By the way, the stacked cooler of this type is formed in a structure inwhich, in order to bring the electronic part into close contact with theflow pipe, a compressive load is applied to the flow pipe in thestacking direction in a state in which the electronic part is arrangedin a space formed between the flow pipes to thereby sandwich theelectronic part by both surfaces of the flow pipes. At this time, theflow pipe has a root part of the protruding pipe part deformed inward bya pressing force, whereby the electronic part is brought into closecontact with the flow pipe.

Here, FIG. 26 is a top view of a flow pipe 80 used in the related art.As shown in FIG. 26, the flow pipe 80 has a peripheral edge part in alongitudinal direction thereof formed in a shape of an arc and has aprotruding pipe part 81 provided at a position separated by a specifieddistance from the peripheral edge part. Specifically, the flow pipe 80is provided with the protruding pipe part 81 in such a way that a centerof the arc of the peripheral edge part in the longitudinal direction isidentical with a center of a section of the protruding pipe part 81. Inthis regard, a flat plane extended between the pair of protruding pipeparts 81 in the flow pipe 80 becomes a heat exchange region 82 in whichthe heat transfer medium exchanges heat with the electronic part.

In the flow pipe 80 of this structure, a region surrounding the rootpart of the protruding pipe part 81 becomes a region to receive thecompressive load in the stacking direction. Of the region surroundingthe root part of the protruding pipe part 81, a semicircular region 83in which a distance from the peripheral edge part in the longitudinaldirection of the flow pipe 80 to the protruding pipe part 81 is shorthas a strongest load applied thereto when the root part of theprotruding pipe part 81 is deformed by the compressive load in thestacking direction. In addition, when a load is applied to thesemicircular region 83 from many directions by vibrations or the like,the semicircular region 83 tends to cause a fatigue failure.

In contrast to this, the present inventors have conducted an earnestinvestigation so as to improve the durability of the flow pipe 80. Asthe result, the present inventors have invented a structure in which, asshown in FIG. 27, a distance from a peripheral edge part in alongitudinal direction in a flow pipe 90 to a protruding pipe part 91 iselongated to thereby expand a region to receive a compressive load inthe stacking direction, whereby the durability of the flow pipe 91 isimproved.

However, when the flow pipe shown in FIG. 27 is employed, a heatexchange region 92 in which the heat transfer medium exchanges heat withthe electronic part is made narrow. In other words, in a case in whichthe flow pipe 90 shown in FIG. 27 is employed, when a heat exchangeregion 92 equivalent to the heat exchange region 82 of the flow pipe 80is ensured, the size in a longitudinal direction of the flow pipe 90needs to be enlarged.

SUMMARY OF INVENTION

The present disclosure addresses the above background art. Thus, it isan objective of the present disclosure to provide a stacked cooler that,when an external force is applied to a refrigerant introduction pipe anda refrigerant discharge pipe, can be restrained from being deformed andcan be reduced in size. Further, it is another objective of the presentdisclosure to provide a stacked cooler capable of ensuring a heatexchange region in which a heat exchange object exchanges heat with aheat medium and of improving the durability of a flow pipe without beingenlarged in size in a longitudinal direction of the flow pipe.

A stacked cooler of a first aspect of the present disclosure includesflow pipes that are stacked, each of the flow pipes having a flat shapeand including a medium passage in which a heat medium flows, a heatexchange object that is disposed between each adjacent two of the flowpipes and is clamped between their flat planes, a protruding pipe partthat is connected to at least one of the flow pipes and protrudes in astacking direction of the flow pipes, and a load restraining part thatrestrains a load applied to a connection portion of the at least one ofthe flow pipes to the protruding pipe part as compared with a loadapplied to the other portion of the at least one of the flow pipes.

A second aspect of the present disclosure is a stacked coolercharacterized by including: a heat exchange part that has a plurality ofcooling pipes arranged in a stacking manner in such a way that theadjacent cooling pipes are coupled to each other and that an arrangementspace used for arranging a heating part is formed between the adjacentflow pipes, the cooling pipe having a refrigerant passage to circulate arefrigerant; a refrigerant introduction pipe to introduce therefrigerant into the refrigerant passage; and a refrigerant dischargepipe to discharge the refrigerant from the refrigerant passage, whereinthe refrigerant introduction pipe and the refrigerant discharge pipe areextended in a stacking direction of the plurality of cooling pipes froma front end cooling pipe arranged at a front end, which is one end inthe stacking direction of the plurality of cooling pipes, and arerespectively provided with a rigidity improving part to improve therigidity of the front cooling pipe.

The stacked cooler is provided with the rigidity improving part toimprove the rigidity of the front end cooling pipe. For this reason,when an external force is applied to the refrigerant introduction pipeand the refrigerant discharge pipe, it is possible to restrain the frontend cooling pipe from being deformed. In this way, when a connectionpart of the front end cooling pipe and the refrigerant introduction pipeand a connection part of the front end cooling pipe and the refrigerantdischarge pipe are reduced in size in order to reduce the size of theheat exchange part, it is possible to restrain the front end coolingpipe from being deformed. In this way, when the external force isapplied to the refrigerant introduction pipe and the refrigerantdischarge pipe, it is possible to restrain the front end cooling pipefrom being deformed and to reduce the size of the stacked cooler.

As described above, according to the stacked cooler described above,when the external force is applied to the refrigerant introduction pipeand the refrigerant discharge pipe, it is possible to restrain the frontend cooling pipe from being deformed and to reduce the size of thestacked cooler.

The stacked cooler of the present disclosure is provided with aplurality of flow pipes each of which is provided with a refrigerantpassage having a heat medium circulated therein and is formed in a flatshape, and a heat exchange object that is arranged in a space formedbetween the adjacent flow pipes and that exchanges heat with the heatmedium.

To achieve the objective, in a third aspect, the heat exchange object isdisposed between each adjacent two of the flow pipes in a stackingmanner such that the heat exchange object is clamped between the flatplanes of the each adjacent two of the flow pipes extending in theirlongitudinal direction. Each of the flow pipes includes the protrudingpipe part having a cylindrical shape that opens in the stackingdirection and protrudes in the stacking direction, and the deformingportion that forms a root part of the protruding pipe part and isdeformed by a compressive load applied in the stacking direction. Ashortest distance from a peripheral edge part of the flow pipe in itsshort direction to the protruding pipe part is longer than a shortestdistance from a peripheral edge part of the flow pipe in itslongitudinal direction to the protruding pipe part.

According to this aspect, a region from a peripheral edge part in theshort direction in the flow pipe to the protruding pipe part, that is, aregion to receive the compressive load applied in the stacking directioncan be expanded. At this time, a region from the peripheral edge part inthe longitudinal direction in the flow pipe to the protruding pipe partdoes not need to be expanded, so it is possible to ensure a flat planeextended in the longitudinal direction in the flow pipe, that is, a heatexchange region in which the heat exchange object exchanges heat withthe heat medium.

Hence, according this aspect, without expanding the size of the stackedcooler in the longitudinal direction in the flow pipe, it is possible toensure the heat exchange region in which the heat exchange objectexchanges heat with the heat medium and to improve the durability of theflow pipe.

In a fourth aspect, the flow pipe includes a pair of peripheral edgeparts extending its longitudinal direction. A shortest distance from acenter of a section of the protruding pipe part in a directionperpendicular to the stacking direction to the peripheral edge part ofthe flow pipe in its longitudinal direction is shorter than a half of alength of each of the pair of peripheral edge parts in its shortdirection.

According to this aspect, the protruding pipe part is made eccentric insuch a way that a center of its section comes near to a peripheral edgepart side in the longitudinal direction, so it is possible tosufficiently ensure a flat plane (heat exchange region) extended in thelongitudinal direction in the flow pipe.

BRIEF DESCRIPTION OF DRAWINGS

The above and other objects, features and advantages of the presentdisclosure will become more apparent from the following detaileddescription made with reference to the accompanying drawings. In thedrawings:

FIG. 1 is a diagram to illustrate a power converter having a stackedcooler in a first embodiment;

FIG. 2 is a section view when viewed from arrows II-II in FIG. 1;

FIG. 3 is a partial section view of the stacked cooler in the firstembodiment (corresponding to section, when viewed from a direction shownby arrows III-III in FIG. 2);

FIG. 4 is a diagram to illustrate a reinforcing plate in the firstembodiment;

FIG. 5 is a view when viewed from a direction shown by an arrow V inFIG. 4;

FIG. 6 is a diagram to illustrate a stacked cooler in a secondembodiment;

FIG. 7 is a partial section view to illustrate a stacked cooler in athird embodiment;

FIG. 8 is a partial section view to illustrate a stacked cooler in afourth embodiment;

FIG. 9 is a front view of a stacked cooler according to a fifthembodiment;

FIG. 10 is a section view taken on a line X-X in FIG. 9;

FIG. 11 is a section view taken on a line XI-XI in FIG. 10;

FIG. 12 is a view when viewed from a direction shown by an arrow XII inFIG. 10;

FIG. 13 is a front view of the stacked cooler according to the fifthembodiment when a compressive load is applied to the stacked cooler in astacking direction;

FIG. 14 is a top view to illustrate a main portion of an end part in alongitudinal direction of a flow pipe according to the fifth embodiment;

FIG. 15 is a section view taken on a line XV-XV in FIG. 14;

FIG. 16 is a section view taken on a line XVI-XVI in FIG. 14;

FIG. 17 is a diagram to illustrate an operation and effect of a flowpipe according to the fifth embodiment;

FIG. 18 is a diagram to illustrate a way in which a heat medium flows ina flow pipe according to the fifth embodiment;

FIG. 19 is a diagram to illustrate a way in which a heat medium flows ina flow pipe according to a comparative example;

FIG. 20 is a diagram to illustrate a way in which the heat medium flowsin the flow pipe according to the fifth embodiment;

FIG. 21 is a diagram to illustrate a way in which the heat medium flowsin the flow pipe according to the comparative example;

FIG. 22 is a top view to illustrate a region in which a brazing materialis arranged in the flow pipe according to the fifth embodiment;

FIG. 23 is a top view of a flow pipe according to a sixth embodiment;

FIG. 24 is a top view of a flow pipe according to a first modifiedexample;

FIG. 25 is a top view of a flow pipe according to a second modifiedexample;

FIG. 26 is a diagram to illustrate a problem; and

FIG. 27 is a diagram to illustrate a problem.

EMBODIMENTS FOR CARRYING OUT INVENTION

Hereinafter, embodiments will be described with reference to thedrawings. In this regard, in the respective embodiments described below,there is a case in which a part equal or equivalent to a matterdescribed in a preceding embodiment is denoted by a same referencecharacter and in which its description is omitted. Further, in therespective embodiments, in a case in which only a part of a constituentelement is described, a constituent element described in a precedingembodiment can be applied to the other part of the constituent element.

In a stacked cooler, a heat exchange part has a front end cooling pipe,a rear end cooling pipe arranged at a rear end in a stacking direction,and a middle cooling pipe interposed between the front end cooling pipeand the rear end cooling pipe, and the rigidity of the front end coolingpipe may be larger than the rigidity of the middle cooling pipe. In thiscase, it is possible to restrain an increase in the weight and in thematerial cost of the middle cooling pipe. In this way, it is possible toreduce the weight and the cost of the stacked cooler and at the sametime to surely restrain the stacked cooler from being deformed.

Further, the rigidity of the front end cooling pipe may be larger thanthe rigidity of the rear end cooling pipe. In this case, by making therigidity of the front end cooling pipe largest among the plurality ofcooling pipes, it is possible to restrain an increase in the weight andin the material cost of the middle cooling pipe and the rear end coolingpipe. In this way, it is possible to reduce the weight and the cost ofthe stacked cooler and at the same time to surely restrain the stackedcooler from being deformed.

Still further, a rigidity improving part is made of a reinforcing plateoverlaid on the front end cooling pipe, and the reinforcing plate mayhas a join part joined to a periphery of a connection part of arefrigerant introduction pipe and a refrigerant discharge pipe in thefront end cooling pipe. In this case, the rigidity of the front endcooling pipe can be surely and easily improved by using the reinforcingplate. In this way, it is possible to surely restrain the front endcooling pipe from being deformed.

First Embodiment

An embodiment relating to the stacked cooler will be described withreference to FIG. 1 to FIG. 5. As shown in FIG. 1 to FIG. 3, a stackedcooler 1 is provided with a heat exchange part 10 in which a pluralityof cooling pipes (flow pipes) 2 are arranged in a stacking manner, arefrigerant introduction pipe 41 which introduces a refrigerant (heatmedium) into a refrigerant passage (medium passage) 20, and arefrigerant discharge pipe 42 which discharges the refrigerant from therefrigerant passage 20. The plurality of cooling pipes 2, each of whichhas the refrigerant passage 20 to circulate the refrigerant, arearranged in a stacking manner in such a way that the adjacent coolingpipes 2 are coupled to each other and that an arrangement space 11 usedfor arranging a semiconductor module 5 as a heating part (heat exchangeobject) is formed between the adjacent cooling pipes 2.

The refrigerant introduction pipe 41 and the refrigerant discharge pipe42 are extended in a stacking direction X from a front end cooling pipe21 arranged at a front end, which is one end in the stacking direction Xof the plurality of cooling pipes 2, of the plurality of cooling pipes2. The stacked cooler 1 has a rigidity improving part 3 to improve therigidity of the front end cooling pipe 21.

The stacked cooler 1 will be described below in more detail. As shown inFIG. 1 and FIG. 2, in the present embodiment, the stacked cooler 1 willbe described on the assumption that: a direction in which the coolingpipes 2 of the stacked cooler 1 are stacked is the stacking direction X;a longitudinal direction in the cooling pipe 2 is a lateral direction Y;and a direction orthogonal to both of the stacking direction X and thelateral direction Y is an up and down direction Z. In the stackingdirection X, a direction in which the refrigerant introduction pipe 41and the refrigerant discharge pipe 42 are protruded is assumed to be afront side and a direction opposite to the front side is assumed to be arear side. Further, in the up and down direction Z, a side in which amain electrode terminal 512 of the semiconductor module 5 is protrudedis assumed to be a lower side and a side opposite to the down side isassumed to be an upper side. In this regard, the stacking direction X,the lateral direction Y, and the up and down direction Z are determinedfor the purpose of convenience and the directions of the stacked cooler1 are not necessarily limited to these directions.

As shown in FIG. 1 and FIG. 2, the stacked cooler 1 of the presentembodiment is used for cooling a plurality of semiconductor modules 5 ina power converter 6. The power converter 6 has a semiconductor unit 61,which is made of the stacked cooler 1 and the plurality of semiconductormodules 5, and a case 7 which receives the semiconductor unit 61.

As shown in FIG. 1 and FIG. 2, the case 7 which receives thesemiconductor unit 61 has a bottom part 71 arranged below and a wallpart 72 erected upward from an outer peripheral edge of the bottom part71. The bottom part 71 is formed in a rectangular shape larger than anoutward form of the semiconductor unit 61 when viewed from above.

The wall part 72 is formed in the shape of a square cylinder erectedupward from the whole circumference of the outer peripheral edge of thebottom part 71. Further, in the wall part 72 arranged on the front sidea pair of through holes 721 is formed in such a way that the refrigerantintroduction pipe 41 and the refrigerant discharge pipe 42 are passedthrough the through holes.

As shown in FIG. 1 and FIG. 2, the plurality of semiconductor modules 5which constitute the semiconductor unit 61 has a main part 511 having aswitching element, a plurality of control terminals 513 extending upwardfrom the main part 511, and a plurality of main electrode terminals 512extending downward from the main part 511.

The semiconductor module 5 has a switching element such as an IGBT(Insulated Gate Bipolar Transistor) or a MOFET (MOS type field effecttransistor) built therein. The main part 511 in the semiconductor module5 of the present embodiment is formed in the shape of a flat plate andis formed by molding one switching element with resin. The controlterminals 513 formed so as to extend upward from the main part 511 areconnected to a control circuit board (not shown in the drawing) and havea control current inputted therein, the control current controlling theswitching element.

As shown in FIG. 1 to FIG. 3, the stacked cooler 1 to cool the pluralityof semiconductor modules 5 has a heat exchange part 10 in which theplurality of cooling pipes are arranged in a stacking manner, therefrigerant introduction pipe 41 to introduce the refrigerant into therefrigerant passage 20, and the refrigerant discharge pipe 42 todischarge the refrigerant from the refrigerant passage 20.

The plurality of cooling pipes 2, which constitute the heat exchangepart 10 and each of which has the refrigerant passage 20 to circulatethe refrigerant, are arranged in the stacking manner in such a way thatthe adjacent cooling pipes 2 are coupled to each other and that thearrangement space 11 used for arranging the semiconductor module 5 isformed between the adjacent cooling pipes 2. The plurality of coolingpipes 2 include the front end cooling pipe 21 arranged at an end on afront side in the heat exchange part 10, a rear end cooling pipe 22arranged at an end on a rear side, and the middle cooling pipes 23arranged between the front end cooling pipe 21 and the rear end coolingpipe 22.

In the present embodiment, the cooling pipe 2 has a front outer shellplate 211 arranged on the front side, a rear outer shell plate 212arranged on the rear side, and a middle plate 213 arranged between thefront outer shell plate 211 and the rear outer shell plate 212.

When the front outer shell plate 211 is joined to the rear outer shellplate 212, a space to form the refrigerant passage 20 is formed betweenthem, and the refrigerant passage 20 is divided into two parts in afront and rear direction by the middle plate 213. The plurality ofcooling pipes 2 are arranged in such a way as to sandwich thesemiconductor module 5 from both faces. The adjacent cooling pipes 2 arecoupled to each other by coupling pipes 43 near both end parts in thelateral direction Y.

As shown in FIG. 1 to FIG. 3, the refrigerant introduction pipe 41 andthe refrigerant discharge pipe 42 are extended forward with the frontend cooling pipe 21 used as a base end Further, the refrigerantintroduction pipe 41 and the refrigerant discharge pipe 42 are extendedin a stacking direction X respectively from base end side pipe parts411, 412 with its diameter expanded in two stages, whereby tip end partsarranged on the front side constitute tip end side pipe parts 412, 422,respectively. In other words, between the base end side pipe part 411and the tip end side pipe part 412, a middle pipe part 413 is formed,the middle pipe part 413 having an outside diameter of a middle ofdiameters of the base end side pipe part 411 and the tip end side pipepart 412, whereas between the base end side pipe part 412 and the tipend side pipe part 422, a middle pipe part 423 is formed, the middlepipe part 423 having an outside diameter of a middle of diameters of thebase end side pipe part 412 and the tip end side pipe part 422. Hence, atapered stepped part 414-1 is formed at a boundary portion between thebase end side pipe part 411 and the middle pipe part 413 and a taperedstepped part 414-2 is formed at a boundary portion between the middlepipe part 413 and the tip end side pipe part 412, whereas a taperedstepped part 424-1 is formed at a boundary portion between the base endside pipe part 421 and the middle pipe part 423 and a tapered steppedpart 424-2 is formed at a boundary portion between the middle pipe part423 and the tip end side pipe part 422.

In the present embodiment, in the refrigerant introduction pipe 41 andthe refrigerant discharge pipe 42, portions on the base end side of thebase end side pipe parts 411, 421 are formed along with the front shellplate 211 of the front end cooling pipe 21 by a press forming, and otherportions closer to the tip end side are formed of separate members andthen are joined to the portions on the base end side, respectively. Therefrigerant introduction pipe 41 and the refrigerant discharge pipe 42are arranged nearly coaxially with the coupling pipes 43, respectively,near the both end parts in the lateral direction Y and are passedthrough the pair of through holes 721 formed in the wall part 72arranged forward of the case 7, respectively.

In the stacked cooler 1, the refrigerant introduced from the refrigerantintroduction pipe 41 is passed through the coupling pipe 43 asappropriate and is distributed into the respective cooling pipes 2 andis circulated in the longitudinal direction (lateral direction Y). Then,the refrigerant exchanges heat with the semiconductor module 5 while therefrigerant flows in the cooling pipes 2. The refrigerant having itstemperature increased by the heat exchange flows through the couplingpipe 43 on a downstream side and is guided to and discharged from therefrigerant discharge pipe 42. As the refrigerant can be used, forexample, a natural refrigerant such as water or ammonia, water mixedwith an ethylene glycol based antifreeze, a carbon fluoride basedrefrigerant such as Fluorinert, a fluorocarbon based refrigerant such asHCFC123 or HFC134a, an alcohol based refrigerant such as methanol oralcohol, and a ketone based refrigerant such as acetone.

As shown in FIG. 1 to FIG. 3, the front end cooling pipe 21 in thestacked cooler 1 is provided with a reinforcing plate 31 as a rigidityimproving part 3, which improves the rigidity of the front end coolingpipe 21, and an engaging claw 25, which temporarily holds thereinforcing plate 31. The reinforcing plate 31 is formed of a nearlyrectangular flat plate and is joined to a front surface of the front endcooling pipe 21 in a join part 312 in such a way that its longitudinaldirection is the lateral direction Y and that its normal direction isthe stacking direction X.

As shown in FIG. 4 and FIG. 5, each of both end parts in the lateraldirection Y of the reinforcing plate 31 has a plate end depressed part311, which is formed so as to be depressed inside in the lateraldirection Y and hence is nearly shaped like a letter U, and has therefrigerant introduction pipe 41 and the refrigerant discharge pipe 42arranged inside the plate end depressed part 311 (see FIG. 2). Further,the width in the up and down direction in the reinforcing plate 31 isset at the same as the width of the front end cooling pipe 21.

The reinforcing plate 31 has two join parts 312. One of the two joinparts 312 is joined to the periphery of the connection part 24 of thefront end cooling pipe 21 and the refrigerant introduction pipe 41, andthe other of the two join parts 312 is joined to the periphery of theconnection part 24 of the front end cooling pipe 21 and the refrigerantdischarge pipe 42. Each of the join parts 312 is formed along an innerperipheral edge in the plate end depressed part 311. In the presentembodiment, each of the join parts 312 is formed in the shape of aletter C along a nearly semicircular periphery on a central side of thelateral direction Y of the front end cooling pipe 21 in the periphery ofthe connection part 24 (see FIG. 3). The whole surface of the join part312 forms a protruding part 313 protruding toward the front end coolingpipe 21. In the present embodiment, the whole surface of the join part312 forms the protruding part 313 but a portion of the join part 312 mayform the protruding part 313.

The reinforcing plate 31 has a pair of engaged parts 32 formedrespectively on both ends in the lateral direction Y, the engaged part32 being engaged by an engaging claw 25. The engaged part 32 is formedin such a way as to extend along the surface of the front end coolingpipe 21 at a position corresponding to the engaging claw 25 of the frontend cooling pipe 21 and to protrude outward in the lateral direction Yfrom the reinforcing plate 31. Further, as shown in FIG. 5, a thin part33 is formed between the join part 312 and the engaged part 32 in thereinforcing plate 31. In the stacking direction X, the thickness of thethin part 33 is set smaller than the thickness of the join part 312.

In a stage before the front end cooling pipe 21 and the reinforcingplate 31 being joined to each other, the temporarily held reinforcingplate 31 is joined to the front surface of the front end cooling pipe 21by brazing. In this way, by joining the reinforcing plate 31 to thefront end cooling pipe 21, the rigidity of the front end cooling pipe 21is made larger than the rigidity of the rear end cooling pipe 22 and therigidity of the middle cooling pipe 23.

As shown in FIG. 1, the semiconductor unit 61, which is formed of thestacked cooler 1 and the plurality of semiconductor modules 5, ispressed by a spring member 73, which biases the semiconductor unit 61 inthe stacking direction X, from a side opposite to a side in which therefrigerant introduction pipe 41 and the refrigerant discharge pipe 42are connected to the semiconductor unit 61. An abutting plate 74, whichrestrains the rear end cooling pipe 22 from being deformed, is arrangedbetween the spring member 73 and the rear end cooling pipe 22.

The operation and effect of the present embodiment will be describedbelow. The stacked cooler 1 has the rigidity improving part 3 to improvethe rigidity of the front end cooling pipe 21. For this reason, when anexternal force is applied to the refrigerant introduction pipe 41 andthe refrigerant discharge pipe 42, it is possible to prevent the frontend cooling pipe 21 from being deformed. In this way, even when theconnection part 24 of the refrigerant introduction pipe 41 and the frontend cooling pipe 21 and the connection part 24 of the refrigerantdischarge pipe 42 and the front end cooling pipe 21 have their diametersreduced in order to reduce the size of the heat exchange part 10, it ispossible to prevent the front end cooling pipe 21 from being deformed.In this way, when the external force is applied to the refrigerantintroduction pipe 41 and the refrigerant discharge pipe 42, it ispossible to restrain the front end cooling pipe 21 from being deformedand at the same time to reduce the size of the stacked cooler 1.

Further, the heat exchange part 10 has the front end cooling pipe 21,the rear end cooling pipe 22 arranged on the rear end in the stackingdirection X, and the middle cooling pipes 23 arranged between the frontend cooling pipe 21 and the rear end cooling pipe 22, and the rigidityof the front end cooling pipe 21 is larger than the rigidity of the rearend cooling pipe 22 and the rigidity of the middle cooling pipe 23. Forthis reason, by making the rigidity of the front end cooling pipe 21largest among the plurality of cooling pipes 2, it is possible torestrain the middle cooling pipes 23 and the rear end cooling pipe 22from being increased in the weight and in the material cost. In thisway, it is possible to reduce the weight and the cost of the stackedcooler 1 and at the same time to surely restrain the front end coolingpipe 21 from being deformed.

Still further, the rigidity improving part 3 is made of the reinforcingplate 31 overlaid on the front end cooling pipe 21. The reinforcingplate 31 has two join parts 312. One of the two join parts 312 is joinedto the periphery of the connection part 24 of the front end cooling pipe21 and the refrigerant introduction pipe 41, and the other of the twojoin parts 312 is joined to the periphery of the connection part 24 ofthe front end cooling pipe 21 and the refrigerant discharge pipe 42. Forthis reason, the rigidity of the front end cooling pipe 21 can beimproved surely and easily by using the reinforcing plate 31. In thisway, it is possible to surely restrain the front end cooling pipe 21from being deformed.

Still further, the reinforcing plate 31 has the protruding part 313protruding toward the front end cooling pipe 21. For this reason, theprotruding part 313 can be brought into contact with the front endcooling pipe 21. In this way, it is possible to surely join thereinforcing plate 31 to the front end cooling pipe 21 in the join part312.

Still further, the front end cooling pipe 21 has the engaging claws 25to hold the reinforcing plate 31 and the reinforcing plate 31 has theengaged parts 32 that can be engaged respectively by the engaging claws25. When the engaging claws 25 engage with the engaged parts 32, thereinforcing plate 31 can be temporarily held by the front end coolingpipe 21. For this reason, a work of joining the reinforcing plate 31 tothe front end cooling pipe 21 can be easily conducted. In this way, itis possible to improve the productivity of the stacked cooler 1.

Still further, the reinforcing plate 31 has the thin part 33 formedbetween the join part 312 and the engaged part 32, the thin part 33being formed in a thinner thickness than the thickness of the join part312. For this reason, when a force is applied to the engaged part 32,the thin part 33 is deformed, which can restrain the force from beingtransferred to the join part 312. In this way, it is possible torestrain the join part 312 from being deformed.

As described above, according to the stacked cooler 1 of the presentembodiment, when the external force is applied to the refrigerantintroduction pipe 41 and the refrigerant discharge pipe 42, it ispossible to restrain the stacked cooler 1 from being deformed and at thesame time to reduce the size of the stacked cooler 1.

In the present embodiment, the reinforcing plate 31 of one member isused. However, the present disclosure is not necessarily limited to thisreinforcing plate 31 but a reinforcing plate 31, which is divided into apart on a refrigerant introduction pipe 41 side and a part on arefrigerant discharge pipe 42 side, can also be used. Further, thereinforcing plate 31, as shown in the present embodiment, may be joinedto a front surface of the front end cooling pipe 21 and may be joined toa rear surface of the front end cooling pipe 21.

Second Embodiment

The present embodiment, as shown in FIG. 6, is an example of a stackedcooler in which the shape of the cooling pipe is partially changed. Inthe stacked cooler 1 of the present embodiment a cooling pipe 2 is usedin which a width in the up and down direction Z is increased.

As shown in FIG. 6, the cooling pipe 2 of the present embodiment has apair of tapered parts 26, formed so as to be increased in width toward acentral side from both end parts when viewed from the stacking directionX, and a pair of wide cooling faces 27, arranged between the pair oftapered parts 26 and sandwiching the semiconductor module 5.

The reinforcing plate 31 joined to the front end cooling pipe 21 isformed in a shape along the outward form of the cooling pipe 2. Thereinforcing plate 31 has a pair of plate tapered parts 34, formed so asto be widened toward a central side from both end parts when viewed fromthe stacking direction X, and a pair of plate wide parts 35, formedbetween the pair of plate tapered parts 34. In this regard, of thereference characters used in the present embodiment or in the drawingsrelating to the present embodiment, the same reference characters as thereference character used in the first embodiment designate the sameconstituent elements as the first embodiment, unless otherwisedesignated.

Also in the present embodiment, the same operation and effect as thefirst embodiment can be produced. Further, the reinforcing plate 31shown in the first embodiment can also be used for the cooling pipe 2increased in width.

Third Embodiment

The present embodiment, as shown in FIG. 7, is an example of therigidity improving part. In the stacked cooler 1 of the presentembodiment, the rigidity improving part 3 has the front outer shellplate 211 of the front end cooling pipe 21 increased in thickness ascompared with the thickness of the rear outer shell plate 212 and thethickness of the middle plate 213. Further, the refrigerant introductionpipe 41 and the refrigerant discharge pipe 42 are formed of a memberseparate from the front outer shell plate 211 and are fitted in thefront outer shell plate 211 and are joined to the front outer shellplate 211 by brazing. In this regard, of the reference characters usedin the present embodiment or in the drawings relating to the presentembodiment, the same reference characters as the reference charactersused in the first embodiment designate the same constituent elements asthe first embodiment, unless otherwise designated.

Also in the present embodiment, the same operation and effect as thefirst embodiment can be produced. Further, in the present embodiment,the front outer shell plate 211 is increased in thickness, but the rearouter shell plate 212 may be increased in thickness.

Fourth Embodiment

The present embodiment, as shown in FIG. 8, is another example of therigidity improving part. As shown in FIG. 8, in the stacked cooler 1 ofthe present embodiment, the rigidity improving part 3 has the middleplate 213 to constitute the front end cooling pipe 21 increased inthickness as compared with the thickness of the front outer shell plate211 and the thickness of the rear outer shell plate 212. In this regard,of the reference characters used in the present embodiment or in thedrawings relating to the present embodiment, the same referencecharacters as the reference characters used in the first embodimentdesignate the same constituent elements as the first embodiment, unlessotherwise designated. Also in the present embodiment, the same operationand effect as the first embodiment can be produced.

Fifth Embodiment

In the present embodiment an embodiment will be described thatconstitutes a cooler to cool a plurality of electronic parts 102 as “aheat exchange object” by using a stacked cooler 101.

The stacked cooler 101, as shown in FIG. 9 and FIG. 10, is constitutedin such a way that a plurality of flow pipes 103, each of which isformed in a flat shape, are stacked in a state in which electronic parts102 are arranged in respective spaces formed between the adjacent flowpipes 103. In this regard, FIG. 10 is a drawing to show an X-X sectionview in FIG. 9 but omits the electronic part 102 so as to clarify theshape of the flow pipe 103.

The electronic part 102 is formed in a flat rectangular shape so as tohave both surfaces thereof sandwiched by the adjacent flow pipes 103. Inthe present embodiment, as the electronic part 102, a semiconductormodule (part constituted of a semiconductor element such as an IGBT anda diode) is employed, which is used for an inverter for a vehicle or amotor driven inverter used for an industrial instrument. In this regard,as the electronic part 102, for example, a power transistor or a powerFET other than the semiconductor module may be employed.

In the flow pipe 103, as shown in FIG. 10, a pair of peripheral edgeparts in a short direction is extended in parallel along thelongitudinal direction, and a pair of peripheral edge end parts in thelongitudinal direction is formed in the shape of a semicircular arc soas to form a semicircle.

The flow pipe 103 of the present embodiment is constituted by stackingmetal plates having a high thermal conductivity such as aluminum orcopper and by joining these metal plates. Specifically, the flow pipe103, as shown in FIG. 11, has a pair of outer shell plates 131, 132, amiddle plate 133 interposed between the pair of outer shell plates 131,132, and wavy inner fins 134 interposed between the outer shell plates131, 132 and the middle plate 133.

Medium passages 30 in which a heat transfer medium (heat medium) flowsare formed between the outer shell plates 131, 132 and the middle plate133. In this regard, as the heat transfer medium can be used, forexample, water mixed with an ethylene glycol based antifreeze, a naturalrefrigerant such as water or ammonia, a fluorocarbon based refrigerantsuch as HFC134a, an alcohol based refrigerant such as methanol oralcohol, and a ketone based refrigerant such as acetone.

The pair of outer shell plates 131, 132 is a plate member constituted ofthe outer shell of the flow pipe 103. The outer shell plates 131, 132are joined to each other by a brazing material arranged on the inside oftheir peripheral edge parts. The brazing material arranged on the insideof the outer shell plates 131, 132 is used also for joining the middleplate 133 and the inner fins 134 to the outer shell plates 131, 132. Inthis regard, the peripheral edge parts in the flow pipe 103 are joinportions in which the outer shell plates 131, 132 are joined to eachother by the brazing material.

The flow pipe 103 of the present embodiment, as shown in FIG. 10, hasclaw parts 3 a formed in the peripheral edge parts extended in thelongitudinal direction of the flow pipe 103. The claw parts 3 aconstitute “reinforcing parts” to reinforce the joining of theperipheral edge parts in the pair of outer shell plates 131, 132 fromthe outside. The claw parts 3 a of the present embodiment are formed atpositions at a specified interval from a protruding pipe part 135, whichwill be described later, of the peripheral edge parts extended in thelongitudinal direction of the flow pipe 103.

Returning to FIG. 11, the middle plate 133 is a rectangular plate memberand is joined to the pair of outer shell plates 131, 132 via the innerfins 134. Although not shown in the drawing, the middle plate 133 has acircular opening formed therein in correspondence to an opening of theprotruding pipe part 135, which will be described later. In this regard,the middle plate 133 may have its peripheral edge part sandwiched by thepair of outer shell plates 131, 132.

The inner fins 134 are members to accelerate heat transfer between theheat transfer medium, which is circulated in the medium passage 30, andthe electronic part 102. The inner fins 134 of the present embodimenthave their end parts in the longitudinal direction positioned by ribs 3b formed inward at the peripheral edge parts extended in thelongitudinal direction of the flow pipe 103 shown in FIG. 10. In thisregard, the ribs 3 b of the present embodiment are formed at positionsat a specified interval from the protruding pipe part 135, which will bedescribed later, of the peripheral edge parts extended in thelongitudinal direction of the flow pipe 103.

Further, on both sides in the longitudinal direction of the flow pipe103, as shown in FIG. 12, the cylindrical protruding pipe parts 135 areprovided which are open in the stacking direction and which protrude inthe stacking direction. The adjacent flow pipes 103 are coupled to eachother by fitting the protruding pipe parts 135 and by joining the sidewalls of the protruding pipe parts 135 to each other. In this regard, ofthe plurality of flow pipes 103, each of the flow pipes 103 other thanthe pair of flow pipes 103 positioned on the outermost side in thestacking direction has a pair of protruding pipe parts 135 formed onboth opposite surfaces opposed to the adjacent flow pipes 103. Incontrast to this, of the plurality of flow pipes 103, each of the pairof flow pipes 103 positioned on the outermost sides in the stackingdirection has the protruding pipe part 135 provided only on one surfaceopposed to the adjacent flow pipe 103.

In the adjacent flow pipes 103, their medium passages 30 communicatewith each other because their protruding pipe parts 135 are joined toeach other. Of the pair of protruding pipe parts 135, one protrudingpipe part 135 functions as a supply header part 111 to supply the heattransfer medium to the medium passage 30 of the respective flow pipes103, whereas the other protruding pipe part 135 functions as a dischargeheader part 12 to discharge the heat transfer medium from the mediumpassages 30 of the respective flow pipes 103.

The flow pipe 103 can be broadly divided into a flat plane 3 c, whichconstitutes a heat exchange region to make the heat transfer mediumcirculated in the medium passage 30 exchange heat with the electronicpart 102, and portions 3 d which constitutes the supply header part 111and the discharge header part 12, respectively.

Each of the portions 3 d which constitute the supply header part 111 andthe discharge header part 12 in the flow pipe 103 is characterized bythe protruding pipe part 135 and a ring-shaped diaphragm part 36 havinga specified width in a root portion (near a root) of the protruding pipepart 135. The diaphragm part 36 is a portion which, when a compressiveload is applied to the flow pipe 103 in the stacking direction, receivesthe compressive load via the protruding pipe part 135 and is deformed tothe inside of the flow pipe 103.

Returning to FIG. 9, of the plurality of flow pipes 103, one of the pairof flow pipes 103 arranged on the outermost side in the stackingdirection has a medium introduction part 4 and a medium discharge part105 connected to both ends in the longitudinal direction thereof, themedium introduction part 4 introducing the heat transfer medium into thestacked cooler 101, the medium discharge part 105 discharging the heattransfer medium from the stacked cooler 101. The medium introductionpart 4 and the medium discharge part 105 are joined to the one flow pipe103 arranged on the outermost side in the stacking direction by using ajoining technique such as a brazing technique.

Here, in order to improve the adhesion of the electronic parts 102 tothe flow pipes 103, as shown in FIG. 13, the stacked cooler 101 isformed in a structure in which the electronic parts 102 and the flowpipes 103 are compressed in the stacking direction by a press machine106 in a state in which the electric parts 102 are arranged in spacesformed between the flow pipes 103, whereby the electronic parts 102 aresandwiched by both surfaces of the flow pipes 103. At this time, thediaphragm part 36 to constitute the root part of the protruding pipepart 135 of the flow pipe 103 is deformed to the inside of the flow pipe103 by the compressive load. In this way, the diaphragm part 36 is aportion to be deformed by the compressive load and hence needs to have ahigher durability than the other portions.

Next, a structure specific to the flow pipe 103 of the presentembodiment will be described by using FIG. 14 to FIG. 16. Here, FIG. 14shows a main portion of the flow pipe 103 (end side in the longitudinaldirection).

The protruding pipe part 135 of the present embodiment is arranged onboth sides in the longitudinal direction in the flow pipe 103. Theprotruding pipe part 135 of the present embodiment is arranged in theflow pipe 103 in such a way that, as shown in FIG. 14, the shortestdistance L1 from the peripheral edge part in the short direction to theprotruding pipe part 135 is made longer than the shortest distance L2from the peripheral edge part in the longitudinal direction to theprotruding pipe part 135.

In this way, a region from the peripheral edge part in the shortdirection to the protruding pipe part 135 in the flow pipe 103 isexpanded more than a region from the peripheral edge end part (end parton the left side of the paper) in the longitudinal direction to theprotruding pipe part 135 in the flow pipe 103. The root part of theprotruding pipe part 135 in the flow pipe 103 is a region in which theflow pipe 103 receives the compressive load in the stacking direction,so that expanding the region from the peripheral edge part in the shortdirection to the protruding pipe part 135 in the flow pipe 103 meansexpanding the region in which the flow pipe 103 receives the compressiveload in the stacking direction.

Here, the shortest distance L2 from the peripheral edge part in thelongitudinal direction to the protruding pipe part 135 is set within arange in which, when the compressive load is applied to the flow pipe103 in the stacking direction, a damage such as a crack or a break isnot caused in the region from the peripheral edge end part (end part onthe left side of the paper) in the longitudinal direction to theprotruding pipe part 135 in the flow pipe 103. In this regard, in theprotruding pipe part 135 of the present embodiment, an outside diameterof a section orthogonal to the longitudinal direction is a value(=D−2×L1) acquired by subtracting a value of two times the shortestdistance L1 (=2×L1) from a distance D in the short direction of the pairof peripheral edge parts extended in the longitudinal direction in theflow pipe 103.

Further, the protruding pipe part 135 is formed in an eccentricstructure in which a center OA of a section in a direction orthogonal tothe stacking direction comes near to the peripheral edge end part(arc-shaped portion) in the longitudinal direction of the flow pipe 103.Specifically, the protruding pipe part 135 is arranged in the flow pipe103 in such a way that the shortest distance L3 from the center OA ofthe section to the peripheral edge part in the longitudinal direction ofthe flow pipe 103 is shorter than a half d (=D/2) of the distance D inthe short direction of the pair of peripheral edge parts extended in thelongitudinal direction in the flow pipe 103.

When an imaginary circle S along the peripheral edge end part(arc-shaped portion) in the longitudinal direction of the flow pipe 103is drawn, the protruding pipe part 135 of the present embodiment isarranged in the flow pipe 103 in such a way that a center OA of asection of the protruding pipe part 135 comes nearer to the peripheraledge end side in the longitudinal direction of the flow pipe 103 than acenter OB of the imaginary circle S. In this regard, the imaginarycircle S is a circle the diameter of which is the distance D in theshort direction of the pair of peripheral edge parts extended in thelongitudinal direction in the flow pipe 103.

Here, FIG. 15 is a section view when the flow pipe 103 is cut at a XV-XVline shown in FIG. 14 in the stacking direction, and FIG. 16 is asection view when the flow pipe 103 is cut at a XVI-XVI line shown inFIG. 14 in the stacking direction.

As described above, in order to bring the electronic parts 102 intoclose contact with the flow pipes 103, the stacked cooler 101 is formedin a structure in which the compressive load is applied to theelectronic parts 102 and the flow pipes 103 in the stacking direction ina state in which the electric parts 102 are arranged in the spacesformed between the adjacent flow pipes 103, whereby the electronic parts102 are sandwiched by both surfaces of the flow pipes 103. At this time,in the flow pipe 103, the diaphragm part 36 which forms the root part ofthe protruding pipe part 135 is deformed to the inside by a pressingforce, whereby an inclined surface 36 a opposite to the protruding pipepart 135 is formed.

The pressing force is most greatly applied to a region in which adistance from the peripheral edge part of the flow pipe 103 to theprotruding pipe part 135 becomes shortest and is gradually decreasedtoward a region (region in which a distance from the peripheral edgepart in the longitudinal direction to the protruding pipe part 135becomes longest) opposite to the above region.

For this reason, in the diaphragm part 36, a bending angle θ1 formed bythe inclined surface 36 a, which is formed in a region in which adistance from the peripheral edge part in the longitudinal direction tothe protruding pipe part 135 becomes shortest, and the flat plane 3 cbecomes larger than a bending angle θ2 in a region opposite to theregion (θ1>θ2). In this regard, the bending angle θ is an angle (acuteangle) in which the inclined surface 36 a formed on the diaphragm part36 is inclined with respect to a direction orthogonal to the stackingdirection.

Further, in the diaphragm part 36, a bending angle θ3 in a region inwhich a distance from the peripheral edge part in the short direction tothe protruding pipe part 135 becomes shortest is smaller than thebending angle θ1 in the region in which the distance from the peripheraledge part in the longitudinal direction to the protruding pipe part 135becomes shortest (θ1>θ3). In this regard, the bending angle θ3 in theregion in which the distance from the peripheral edge part in the shortdirection to the protruding pipe part 135 becomes shortest is largerthan the bending angle θ2 in a region in which a distance from theperipheral edge part in the longitudinal direction to the protrudingpipe part 135 becomes longest (θ1>θ3>θ2).

In the stacked cooler 101 constituted in this way, the heat transfermedium introduced from the medium introduction part 4 flows in from oneend part side in the longitudinal direction of each flow pipe 103 viathe supply header part 111 and flows toward the other end part side inthe medium passage 30 of each flow pipe 103. Then, the heat transfermedium flowing in the medium passage 30 is discharged from the mediumdischarge part 105 via the discharge header part 12. At this time, therespective electronic parts 102 sandwiched by the flat planes 3 c of therespective flow pipes 103 exchange heat with the heat transfer mediumflowing in the medium passage 30, thereby being cooled.

Next, the operation and effect of the stacked cooler 101 constituted inthe above manner will be described.

The stacked cooler 101 of the present embodiment, as shown in FIG. 14,the shortest distance L1 from the peripheral edge part in the shortdirection of the flow pipe 103 to the protruding pipe part 135 is longerthan the shortest distance L2 from the peripheral edge part in thelongitudinal direction of the flow pipe 103 to the protruding pipe part135 (L1>L2).

According to this, a region from the peripheral edge part in the shortdirection of the flow pipe 103 to the protruding pipe part 135, that is,a region in which the flow pipe 103 receives the compressive loadapplied in the stacking direction can be expanded. At this time, aregion from the peripheral edge part in the longitudinal direction ofthe flow pipe 103 to the protruding pipe part 135 does not need to beexpanded, so that the flat plane 3 c extended in the longitudinaldirection of the flow pipe 103, that is, the heat exchange region inwhich the electronic part 102 exchanges heat with the heat transfermedium can be secured.

Here, the effect of the flow pipe 103 of the present embodiment will bedescribed by using the flow pipe 103 of the present embodiment shown onan upper side in FIG. 17 and a flow pipe 3′ of a comparative exampleshown on a lower side in FIG. 17. In this regard, it is assumed that, inthe flow pipe 3′ of the comparative example, an outside diameter of asection orthogonal to a longitudinal direction of a protruding pipe part35′ is a value (=D−2×L2) acquired by subtracting a value (=2×L2) of twotimes the shortest distance L2 from a length D in a short direction of apair of peripheral edge parts extended in the longitudinal direction inthe flow pipe 3′.

In the flow pipe 3′ of the comparative example, when a compressive loadin the stacking direction is applied to the flow pipe 3′, the largestload is applied to a semicircular shaded region 36 b′ shown in FIG. 17of a diaphragm part 6′ surrounding a root part of the protruding pipepart 35′. Then, when a load is applied to the flow pipe 3′ from variousdirections by vibrations or the like, a fatigue failure or the liketends to be easily caused in the semicircular shaded region 36 b′.

In contrast to this, in the flow pipe 103 of the present embodiment,when a compressive load in the stacking direction is applied to the flowpipe 103, the largest load is applied to a shaded region 36 b of an endportion in the longitudinal direction shown in FIG. 17 of the diaphragmpart 36 to surround the root part of the protruding pipe part 135.

The shaded region 36 b of the flow pipe 103 of the present embodiment,as shown in FIG. 17, is smaller in area than the shaded region 36 b′ ofthe flow pipe 3′ of the comparative example, so that a fatigue failureor the like by vibrations or the like is not frequently caused in theshaded region 36 b of the flow pipe 103 as compared with the flow pipe3′ of the comparative example.

Further, in the flow pipe 3′ of the comparative example, an outsidediameter of a section orthogonal to the longitudinal direction of theprotruding pipe part 35′ is a value (=D−2×L2) acquired by subtracting avalue (=2×L2) of two times the shortest distance L2 from a length D inthe short direction of the pair of peripheral edge parts extended in thelongitudinal direction in the flow pipe 3′.

In contrast to this, in the flow pipe 103 of the present embodiment, anoutside diameter of a section orthogonal to the longitudinal directionof the protruding pipe part 135 is a value (=D−2×L1) acquired bysubtracting a value (=2×L1) of two times the shortest distance L1 from alength D in the short direction of the pair of peripheral edge partsextended in the longitudinal direction in the flow pipe 103. Then, inthe flow pipe 103 of the present embodiment, the protruding pipe part135 is constituted so as to be eccentric in such a way that a center ofa section comes near to the peripheral edge part side in thelongitudinal direction.

According to this, a length Lx in the longitudinal direction of the flatplane 3 c in the flow pipe 103 can be made longer than a length Lx′ inthe longitudinal direction of a flat plane 3 c′ in the flow pipe 3′ ofthe comparative example. In this way, in the present embodiment, aregion occupied by the flat plane 3 c in the flow pipe 103 can be madelarger than a region occupied by the flat plane 3 c′ in the flow pipe 3′of the comparative example.

By the way, the flat plane 3 c of the flow pipe 103 is a portion withwhich the electronic part 102 is brought into close contact and hence isincreased in pressure resistance than the other portion. As describedabove, in the flow pipe 103 of the present embodiment, the region of theflat plane 3 c can be expanded as compared with the flow pipe 3′ of thecomparative example. Hence, as the region of the flat plane 3 c isexpanded, the flow pipe 103 is improved in the pressure resistance. Inother words, in the present embodiment, the stacked cooler 101 as awhole can be improved in the pressure resistance.

Further, a portion itself in which a bending angle θ formed by theinclined surface 36 a and the flat plane 3 c in the diaphragm part 36 islarge becomes a flow resistance to inhibit a flow of the heat transfermedium flowing into the respective flow pipes 103 and a flow of the heattransfer medium flowing out of the respective flow pipes 103.

Still further, in the portion in which the bending angle θ, which isformed by the inclined surface 36 a and the flat plane 3 c in thediaphragm part 36, is large, when the compressive load is applied to theflow pipe 103 in the stacking direction, a reaction force opposed to thecompressive load becomes large. This reaction force is applied in adirection to separate the flat plane 3 c of the flow pipe 103 from theelectronic part 102, so the reaction force causes to reduce the closecontact of the flat plane 3 c of the flow pipe 103 and the electronicpart 102.

In contrast to this, in the flow pipe 103 of the present embodiment, asshown in FIG. 15 and FIG. 16, a bending angle θ3, which is formed by theinclined surface 36 a formed at the root part on the peripheral edgepart side in the short direction and the flat plane 3 c, is smaller thana bending angle θ1, which is formed by the inclined surface 36 a formedat the root part on the peripheral edge part side in the longitudinaldirection and the flat plane 3 c.

If the bending angle θ on the peripheral edge part side in the shortdirection in the diaphragm part 36 is made small in this way, the flowresistance of the flow of the heat transfer medium on the peripheraledge side in the short direction in the diaphragm part 36 can be madesmall. As the result, the heat transfer medium can easily flow into therespective flow pipes 103 from the peripheral edge part side in theshort direction in the diaphragm part 36 and can easily flow out to theperipheral edge part side in the short direction in the diaphragm part36 from the respective flow pipes 103.

Further, If the bending angle θ3 on the peripheral edge part side in theshort direction in the diaphragm part 36 is made small, when thecompressive load is applied to the flow pipe 103 in the stackingdirection, the reaction force applied to the peripheral edge side in theshort direction in the diaphragm part 36 can be made small. As theresult, it is possible to restrain the close contact of the flat plane 3c of the flow pipe 103 and the electronic part 102 from being reduced.

Here, the flow of the heat transfer medium in the flow pipe 103 of thepresent embodiment will be described by using the flow pipe 103 of thepresent embodiment shown in FIG. 18 and the flow pipe 3′ of thecomparative example shown in FIG. 19. In this regard, it is assumed thatin the flow pipe 3′ of the comparative example, the outside diameter ofa section orthogonal to the longitudinal direction of the protrudingpipe part 35′ is a value acquired by subtracting a value of two timesthe shortest distance L2 from the length D in the short direction of thepair of peripheral edge parts extended in the longitudinal direction inthe flow pipe 3′.

In the flow pipe 103 of the present embodiment, as shown in FIG. 18 andFIG. 19, the bending angle θ3 on the peripheral edge part side in theshort direction in the diaphragm part 36 is smaller than the bendingangle θ3′ of the same portion in the flow pipe 3′ of the comparativeexample. In this regard, the bending angle θ3′ on the peripheral edgepart side in the short direction in the diaphragm part 36′ of the flowpipe 3′ is as large as the bending angle θ1 on the peripheral edge partside in the longitudinal direction in the diaphragm part 36 of the flowpipe 103 of the present embodiment.

For this reason, in the flow pipe 103 of the present embodiment, theheat transfer medium can easily flow into the respective flow pipes 103from the peripheral edge part side in the short direction in thediaphragm part 36 as compared with the flow pipe 3′ of the comparativeexample. In this way, in the flow pipe 103 of the present embodiment, itis possible to restrain the heat transfer medium from being reduced inflow rate in the short direction (flow rate distribution) in the mediumpassage 30 as compared with the flow pipe 3′ of the comparative example(see flow rate distribution shown on the right side in FIG. 18 and FIG.19).

In this way, in the stacked cooler 101 of the present embodiment, it ispossible to restrain the flow rate distribution in the medium passage 30of each flow pipe 103. Hence, in the flow pipe 103, it is possible tomake the electronic part 102 suitably exchange heat with the heattransfer medium.

Further, in the flow pipe 103 of the present embodiment, the peripheraledge end part in the longitudinal direction is formed in the shape ofthe arc. Further, as shown in FIG. 14, the center OA of the section in adirection orthogonal to the stacking direction in the protruding pipepart 135 is positioned closer to the peripheral edge end part in thelongitudinal direction in the flow pipe 103 than the center OB of thearc of the peripheral edge end part in the longitudinal direction in theflow pipe 103.

According to this, as shown in FIG. 20, the heat transfer medium flowingto the peripheral edge part side in the short direction of theprotruding pipe part 135 can easily flow in one direction (to the rightside on the paper) from an inlet side to an outlet side of the mediumpassage 30 by using the peripheral edge part formed in the shape of thearc in the short direction in the flow pipe 103 as a guide part.

Here, FIG. 21 shows a flow pipe 3′ which has a protruding pipe part 35′having the same section diameter as the protruding pipe part 135 shownin FIG. 20 and which is located at the same position as the center OB ofthe arc of the peripheral edge end part in the longitudinal direction inthe flow pipe 103. In this regard, FIG. 21 is the flow pipe 3′ that is acomparative example of the flow pipe 103 of the present embodiment.

In the flow pipe 3′ shown in FIG. 21, the heat transfer medium flowingto the peripheral edge part side in the short direction of theprotruding pipe part 135 can easily flow in the shape of a letter U onthe inlet side of the medium passage 30 along the peripheral edge partformed in the shape of the arc in the longitudinal direction by usingthe peripheral edge part formed in the shape of the arc in thelongitudinal direction in the flow pipe 103 as a guide part. In thisway, it is not preferable that the heat transfer medium turns its flowin the shape of the letter U, because a flow rate distribution in theflow pipe 103 is increased.

In contrast to this, in the flow pipe 103 of the present embodiment, asdescribed above, the heat transfer medium can easily flow in the onedirection (to the right side on the paper) from the inlet side to theoutlet side of the medium passage 30, which hence can reduce the flowrate distribution in the flow pipe 103. As the result, in the flow pipe103, it is possible to make the electronic part 102 suitably exchangeheat with the heat transfer medium.

Further, the flow pipe 103 of the present embodiment is constituted soas to join the pair of outer shell plates 131, 132, which constitute itsouter shell, to each other by the brazing material arranged on theirinsides. The brazing material is collected in a fused state in theperipheral edge parts of the join portion of the pair of outer shellplates 131, 132 and then is cured in a manufacturing process of the flowpipe 103, whereby the peripheral edge parts of the pair of outer shellplates 131, 132 are joined to each other.

As described above, the flow pipe 103 of the present embodiment isconstituted in such a way that the region from the peripheral edge partin the short direction of the pipe 103 to the protruding pipe part 135is expanded. As the result, as shown in FIG. 22, an area of each ofportions 36 c (shaded portions in FIG. 22) is also expanded in which thebrazing material is arranged in the periphery of the protruding pipepart 135 of the pair of outer shell plates 131, 132.

For this reason, the amount of the brazing material to be collected inthe join portion of the pair of outer shell plates 131, 132 can beincreased in the manufacturing process of the flow pipe 103 by expandingthe region from the peripheral edge part in the short direction of thepipe 103 to the protruding pipe part 135. As the result, the outer shellplates 131, 132 can be more reliably joined to each other.

Further, the flow pipe 103 of the present embodiment, as shown in FIG.10, is constituted in such a way that the rib 3 b for positioning theedge part in the longitudinal direction of the inner fin 134 is formedin the peripheral edge part extended in the longitudinal direction inthe flow pipe 103. As described above, the flow pipe 103 of the presentembodiment is constituted so as to expand the region from the peripheraledge part in the short direction of the flow pipe 103 to the protrudingpipe part 135. For this reason, a distance from the rib 3 b to theprotruding pipe part 135 can be sufficiently ensured, which hence canrestrain the rib 3 b from affecting the deformation of the diaphragmpart 36 to form the root part of the protruding pipe part 135.

Still further, the flow pipe 103 of the present embodiment isconstituted so as to have the claw parts 3 a to reinforce the joining ofthe peripheral edge parts in the pair of outer shell plates 131, 132from the outside. As described above, the flow pipe 103 of the presentembodiment is constituted in such a way that the region from theperipheral edge part in the short direction of the flow pipe 103 to theprotruding pipe part 135 is expanded. For this reason, a distance fromthe claw part 3 a to the protruding pipe part 135 can be sufficientlyensured as is the case with the rib 3 b. Hence it is possible torestrain the claw part 3 a from affecting the deformation of thediaphragm part 36 to form the root part of the protruding pipe part 135.

Sixth Embodiment

Next, a sixth embodiment will be described. In the present embodiment,an example will be described in which the shape of the flow pipe 103 ischanged. In this regard, the descriptions of the parts equal orequivalent to the fifth embodiment will be omitted or simplified.

In the flow pipe 103 of the present embodiment, as shown in FIG. 23, theshape of the peripheral edge end part in the longitudinal direction isformed not in the shape of a semi-circular arc but in the shape of atriangle. In this regard, in the flow pipe 103, an outermost vertexportion of the peripheral edge end part in the longitudinal directionside is formed in a round shape so as to draw an arc.

The other configurations and operations are the same as those in thefifth embodiment. In the flow pipe 103 of the present embodiment, theshortest distance from the peripheral edge part in the short directionof the flow pipe 103 to the protruding pipe part 135 is longer than theshortest distance L2 from the peripheral edge part in the longitudinaldirection of the flow pipe 103 to the protruding pipe part 135. Hence,also in the stacked cooler 101 of the present embodiment, the sameeffect as the effect described in the fifth embodiment can be produced.

In this regard, the shape of the peripheral edge end part in thelongitudinal direction in the flow pipe 103 may be formed in a shapeother than the semicircular arc or the triangle if the shape can makethe shortest distance from the peripheral edge part in the shortdirection to the protruding pipe part 135 longer than the shortestdistance L2 from the peripheral edge part in the longitudinal directionto the protruding pipe part 135.

Up to this point, the embodiments have been described. However, thepresent disclosure is not limited to the embodiments described above butcan be variously modified within a scope claimed in the claims. Forexample, the present disclosure can be variously modified as describedbelow.

(1) In the respective embodiments described above the examples have beendescribed in which the flow pipe 103 is provided with the cylindricalprotruding pipe part 135. However, the present disclosure is not limitedto this but, for example, as shown in FIG. 24, the flow pipe 103 may beprovided with a cylindrical protruding pipe part 135 the section ofwhich is oval.

(2) In the respective embodiments described above the examples have beendescribed in which the flow pipe 103 has the pair of protruding pipeparts 135 provided on both end sides in the longitudinal directionthereof. However, the present disclosure is not limited to this but, forexample, as shown in FIG. 25, the flow pipe 103 may have a U-shapedmedium passage 30 formed therein and may have the pair of protrudingpipe part 135 provided on one end part in the longitudinal directionthereof.

(3) In the respective embodiments described above the examples have beendescribed in which the flow pipe 103 has the middle plate 133 arrangedtherein and in which the flow pipe 103 has two rows of medium passages30 arranged therein. However, the present disclosure is not limited tothis but, for example, the middle plate 133 may be omitted and the flowpipe 103 may have one row of medium passage 30 arranged therein.Alternatively, the flow pipe 103 may have two or more middle plates 133arranged therein and may have three or more rows of medium passages 30arranged therein.

(4) In the respective embodiments described above the examples have beendescribed in which the flow pipe 103 has the inner fins 134 arrangedtherein. However, the present disclosure is not limited to this but theinner fins 134 may be omitted.

(5) In the respective embodiments described above the examples have beendescribed in which the peripheral edge parts of the pair of outer shellplates 131, 132 are joined to each other by the brazing material tothereby form the flow pipe 103. However, the present disclosure is notlimited to this, but the flow pipe 103 may be formed by joining theperipheral edge parts of the pair of outer shell plates 131, 132 by ajoining material other than the brazing material.

(6) As described above, it is preferable that the flow pipe 103 isprovided with the claw parts 3 a for reinforcing the joining of theperipheral edge parts of the pair of outer shell plates 131, 132 fromthe outside. However, the present disclosure is not limited to this butthe claw parts 3 a may be omitted.

(7) In the respective embodiments described above the examples have beendescribed in which the stacked cooler of the present disclosure isapplied to a cooler to cool the electronic part 102. However, thepresent disclosure is not limited to this, that is, the stacked coolerof the present disclosure may be applied to a cooler to cool a partother than the electronic part 102 or a heater to heat the part.

(8) In the respective embodiments described above, needless to say,elements to constitute the embodiments are not always essential exceptfor a case in which the elements are clearly designated to be especiallyessential or a case in which the elements are thought to be essential inview of principle.

(9) In the respective embodiments described above, in a case in which anumerical value of the number, the numerical value, the amount, or therange of the constituent element of the embodiment is referred to,except for a case in which the numerical value is clearly designated tobe especially essential or a case in which the numerical value islimited to a specific number in view of principle, the presentdisclosure is not limited to the specific numerical value.

(10) In the respective embodiments described above, when a shape, aposition relationship, or the like of the constituent element or thelike is referred to, except for a case in which a shape, a positionrelationship, or the like is specifically specified and a case in whichthe shape, the position relationship, or the like is limited to aspecific shape or a specific relationship, or the like in view ofprinciple, the present disclosure is not limited to the specific shape,the specific position relationship, or the like.

While the present disclosure has been described with reference to theembodiments thereof, it is to be understood that the present disclosureis not limited to the embodiments and constructions. The presentdisclosure is intended to cover various modifications and equivalentarrangements. In addition, while the various combinations andconfigurations, other combinations and configurations, including more,less or only a single element, are also within the spirit and scope ofthe present disclosure.

What is claimed is:
 1. A stacked cooler comprising: a heat exchange partthat includes a plurality of flow pipes arranged side by side, such thateach adjacent two of the plurality of flow pipes are coupled togetherand define therebetween an arrangement space for disposing a heatexchange object wherein each of the plurality of flow pipes includes amedium passage in which a heat medium flows; a refrigerant introductionpipe for introducing refrigerant into the medium passage; a refrigerantdischarge pipe for discharging the refrigerant from the medium passage,wherein the refrigerant introduction pipe and the refrigerant dischargepipe extend out in a stacking direction of the plurality of flow pipesfrom a front end cooling pipe of the plurality of flow pipes that islocated at their front end, which is one end in the stacking direction;and a rigidity improving part that improves a rigidity of the front endcooling pipe, wherein: the front end cooling pipe includes: a frontouter shell plate that is disposed on its front side; and a rear outershell plate that is disposed on its rear side and is joined to the frontouter shell plate to define a space serving as the medium passagebetween the rear outer shell plate and the front outer shell plate; therefrigerant introduction pipe and the refrigerant discharge pipe arejoined to the front outer shell plate; and at least a thickness of thefront outer shell plate is larger than a thickness of the rear outershell plate to serve as the rigidity improving part. 2-4. (canceled) 5.The stacked cooler according to claim 1, wherein: the heat exchange partincludes the front end cooling pipe, a rear end cooling pipe disposed atits rear end in the stacking direction, and a middle cooling pipedisposed between the front end cooling pipe and the rear end coolingpipe; and the rigidity of the front end cooling pipe is larger than arigidity of the middle cooling pipe.
 6. The stacked cooler according toclaim 5, wherein the rigidity of the front end cooling pipe is largerthan a rigidity of the rear end cooling pipe.
 7. The stacked cooleraccording to claim 1 further comprising a reinforcing plate overlaid onthe front end cooling pipe as the rigidity improving part; wherein thereinforcing plate includes a join part that is joined around each ofconnection parts of the front end cooling pipe to the refrigerantintroduction pipe and the refrigerant discharge pipe.
 8. The stackedcooler according to claim 7, wherein the reinforcing plate includes aprotruding part, which protrudes toward the front end cooling pipe, atthe join part.
 9. The stacked cooler according to claim 7, wherein: thefront end cooling pipe includes an engaging claw that holds thereinforcing plate; the reinforcing plate includes an engaged part thatis capable of being engaged with the engaging claw; and the engaged partis engaged with the engaging claw, so that the reinforcing plate iscapable of being temporarily held by the front end cooling pipe.
 10. Thestacked cooler according to claim 9, wherein: the reinforcing plateincludes a thin part between the join part and the engaged part; and thethin part is formed to have a thickness smaller than a thickness of thejoint part. 11-17. (canceled)